Many display devices have been mounted to automobiles to show various images. The images displayed on the devices include those from a navigation system, those from an onboard audio system, those indicating driving information on the automobile (speed, traveled distance, direction, remaining amount of fuel, etc.), those from security cameras mounted around the automobile, and those from a television receiver.
A recent development is an onboard dashboard with a display screen at a large aspect ratio (elongated widthwise) extending from close to the driver seat to close to the front passenger's seat. The display screen is divided into a driver-side display area and a passenger-side display area. Different images are shown in display areas. See Japanese published patent application 6-195056/1994 (Tokukaihei 6-195056; published on Jul. 15, 1994, paragraph [0049].
The information needed by the driver (for example, the aforementioned driving-related information) is shown in the driver-side display area on the display screen. The information needed by a fellow passenger (for example, television image) is shown in the passenger-side display area on the display screen.
The display screen is thus capable of simultaneously displays of the information needed by the driver and information needed by a fellow passenger.
The display screen however has following problems. The driver-side display area, where driving-related information, etc. is being displayed in a typical situation, has relatively low luminance. Suppose that the passenger-side display area is showing a television image or movie, there are probably involved some scenes which require significantly elevated levels of luminance in the passenger-side display area. The resultant level of luminance in the passenger-side display area may be higher than that in the driver-side display area. Illumination in the passenger-side display area can be glaring relative to the driver-side display area. The driver possibly has trouble recognizing the display in the driver-side display area. So, illumination in the passenger-side display area may be a cause that disrupts driver's visibility.
The present invention, conceived in view of the problems, has an objective to provide a display device with separate display areas for images shown to the driver and those shown to a fellow passenger. The display device must be of a kind that ensures good visibility for the image shown to the driver. Other objectives are to provide a method of controlling the display device, a computer program of controlling the display device, and a computer program storage medium.